Grinding wheel mounting



Nov. 13, 1945. v4R, LQMBARD 2,388,697

GRINDING WHEEL MOUNTING Filed March 28, 1944 POBET H. LOMBARD Patented Nov. 13, 1945 l UNITED STAT/Es i f 2,388,697 l l assetti Gammo si. Moens Robert H. Lombard, Worcter, Mass., assigner to Norton Company, Weser, m

tion of Massachusetts r1., a acera Application March 28, i944, Seriell No. tti

i e.. (ci. simios) This invention relates to the mounting oi grinding wheels, particularly wheels of thevitri- `fied-bonded type, on a rotatable driving support,

Another 'object is to provide a mounting of the l0 above-mentioned nature in which the clamping oi' the wheel may be reliably 'eilected in a manner to guard against shifting of the wheel off-center andv hence to guard against the need of frequent resaving in time and labor as well as saving in the grinding wheel construction itself inasmuch as frequent re-trueing where the abrasive employed is diamond grit is costly. Another object is to provide a grinding wheel mounting construction whole.

in which the clamping pressure is applied to the wheel face or faces underlying the clamping ele- -inent or elements by means that eects dependable distribution of the clamping pressures to avoid concentrations of strains or stresses in the wheel structure and that has an inherent resiliency appropriate to give it good recovery upon release of the clamping pressure, .so that it may be employed over and over again with effective action; another object is to provide a means of the last-mentioned character that will be inexpensive, long-lasting, unaffected by liquids commonly employed as a coolant in grinding wheel operations, unaffected by moisture, and unafl'ect- 35 ed by changes in temperature. Another object is to provide a grinding wheel unit comprising a grinding wheel having attachedthereto, on one or both of its side faces, annular or disk-like members having characteristics such as those just 40 mentioned, for assembly as a unit to a shaft or the like having clamping elements. Another object is in general to provide an improved, more eilicient, long-lasting and reliable grinding wheel unit of the just-mentioned kind. Other objects will be in part obvious or in pointed out herei inafter.

The invention accordingly consists in the features of construction, combinations of elements,

In the accompanying drawing, the single gure is a central or diametrical sectional view of a 55 grinding wheel mounting illustrating one of various possible ways of carrying out my invention.

as conductive to a clearer understanding of certain features of my invention, let it be assumed by way oi illustration, but not by way of limitation, that the grinding wheel it is of the vitriied or ceramic type and also that it employs diamond grit as the active abradant; it may, therefore; have a main body. or center ita made up, for example, of any suitable fired Vceramic or vitriflable bonding mater-iai with or without suitable illler which may comprise such materials as grains koi silicon carbide or of alumina, and an outer abrasive annulus ith oi small radial dimension, trueing due to oir-center shifts, and thus to eReot 15 may 'be the same as lthat employed in the sup-v porting center iti, the two portions being tired as a unit and hence forming one single integral Because of the costliness of the diamond abrasive, the abrasive annulus i0h is of small radial dimension as above noted and to avoid costly` Waste, it ishighly desirable to avoid having to true the operative or grinding face of the annulus ith excepting at such times as when initially mounting the wheel and for subsequent dressing of the abrasive surface during the continued operation of the wheel.

The grinding wheel I0 is provided with a suitable hole at its center to mount it on a shaft. The hole may in some cases be hushed, as by a bushing il of a metal like lead or Babbitt metal or analogous alloy, usually cast in position and thereafter the hole l2 of the bushing is given, as

by drilling or reaming, a true cylindrical surface of the desired diameter. In any case, the surface of the mounting hole is intended to be coaxial or concentric with the grinding surface of the abrasive "annulus I0", and its diameter is such as makes a snug but relatively easy fit with respect to a shaft or stud I3 or the like onto which the wheel is to be mounted for driving at a peripheral grinding speed. Sometimes some play or looseness of fit develops particularly after repeated removals orreplacements of the same wheel with respect to its supporting shaft. More frequently, looseness or play occurs because of variations in the intended diameter of the shaft or stud, some and arrangements of parts all as will be exempliiled in the structure to be hereinafter deshaft being more worn than others, for example. It is possible therefore that the wheel, when initially mountedon the stud or shaft I3 is slightly ofi-center, a condition which is reotiiled by true'- ing or dressing the wheel after it is clamped onto the shaft Il, but thereafter it is possible for an unintentional radial shift to take place of the wheel relative to the shaft I3 to the extent of the above-mentioned play or looseness with the result that the resultant eccentricity of the grinding surface has to be corrected by again trueing or redressing. 'I'hus it is possible to effect costly waste, and prior attempts to overcome such disadvantages, as by the use, for example, of suitable thicknesses of nbrous or so-called "blotting paper" through which tc transmit the clamping pressure to the wheel have not always met with success, for various reasons; for example, the blotting paper or so-called "blotters are detrimentally affected by water; oils, emulsions and other liquid coolants and undergo deterioration or other physical change so that a sufficient looseness or relief cf the clamping pressures takes place to permit a radial shifting ofthe wheel relative to its supporting shaft. Other materials have heretofore been proposed; for example, materials like leather, cloth and the like, but they are not only attacked by certain coolants but also are subject to deterioration from other causes, such as drying out and becoming brittle in the c ase of leather, and rotting or disintegration in the case of cloths. Moreover, most if not all of the materials heretofore proposed are dencient or entirely lacking in proper or desirable coactions withthe clamping plate or plates, both during continued operation of the mounted wheel and upon release of the clamping pressure when the wheel is demounted; in the former case the materials appear to sun'er from mechanical fatigue, often brought about by deterioration such as above mentioned, and thus fail toexert a proper follow-up action in transmitting clamping pressures, with the result that sumcient looseness develops to permit radial shift of the wheel. In the latter case, that is upon release of the clamping pressure upon demounting of the wheel. the materials, having undergone compression against the wheel surfaces by the clamping element or elements, fail to make any or sufficient mechanical or physical recovery as they should in order to ready them for proper functioning the next time.

that the wheel is again mounted on a driving shaft or stud; they thus thereafter permit relatively quick radial shift of the wheel and moreover, because increased clamping vpressures are thereafter employed by the operator in the endeavor to overcome thedeflciency, there is at once brought about grave risk of breaking the wheel, a risk that is enhanced by the failure of the material to compensate for possible unevenness of side faces of the wheel with resultant nonuniform transmission of the clamping pressures from the clamping plate or plates to the wheel center or wheel structure itself, In accordance with my invention I am enabled to provide a wheel mounting in which such deficiencies as those just mentioned are in substantial measure overcome.

According to my invention, I interpose between the side faces of the wheel III and the relatively heavy clamping elements I4 and I5, between which the wheel I0 is clamped in position on the shaft I3 as by a nut I6 which clamps the assemblage against a suitable shoulder II provided on the other end of the stud I3, elements I8 which are annular or disk-like in shape and are of sumcient radial extent to underlie the faces Il* and I5, respectively, of the clamping members I4 and I5. 'I'he latter are generally in the form of heavy strong disks, having holes in them to accommodate the shaft I3 and to substantially center them 75 tion as a multiple or composite Spring. In mat or nx them coaxially withthe shaft I3: preferably, they are under-cut as at I4b and IB where it is desired to avoid applying clamping pressure too close to the innermost or central portions of the grinding wheel I0. As indicated in the drawing, the radial dimension of the-elements I. is greater than the radial dimension of the clamping faces Il* and I 5* of the clamping members I4 and I5.

The elements I8 are preferably made up in sheet-like form out of spun glass nbre, sometimes known as nbre glass. and the glass nbres may be woven or inter-engaged in anyl desired manner to make up a fabric or mat of any desired thickness: the glass nbre may, for example, be processed in a manner analogous to the making up of various textiles. Thus, the glass nbres may be built up or spun, if desired.' into yarn of as many individual fibres as desired and the resultant yarn then inter-locked or inter-woven according to any desired and suitable textile practice. Thus, also, the glass fibres or strands thereof may be simply made up into a suitable mat with the nbres more or less indiscriminately arranged for inter-locking or inter-engagement to hold them together as a mat, with sunicient uniformity of distribution to achieve substantial uniformity lof thickness. Several such fabrics or mats may be superimposed upon one another, preferably held together by any suitable means, such as fibreinterlocking, thus forming a composite or 1aminated textile fabric or nbrous mat of the desired thickness.` Any of the commercially available glass nlaments may be used, both as to available thicknesses and chemical compositions; and also as to lengths, such as so-called continuous" glass nbres of unlimited length or short nbres called "staple.

Illustratively, I employ so-called fibre glass mats or, preferably, so-calied nbre glass cloth, made of glass flbres and both available on the market in various forms, with the textile form or cloth being available in various weaves, etc., etc. For convenience, I comprehend all such forms within the term mat or mat element used in the claims, in which I also term any of the above described inter-relationships of glass nbres as "woven without specific regard to whether it is an actual weave of fibres or yarn as distinguished from knitting or is a criss-crossing of fibres or yarns, or is any other form of glass flbre or yarn inter-relationship. If desired'and as above mentionedl several sheets or layers of glass nbre fabric, such as fibre glass cloth, may be superimposed one upon the other to make up a single element I8 of the desired thickness. Illustratively, for an 8" vitried wheel the elements I8 may be of a thickness on the order of slr" and the weave can be any standard weave.

The criss-crossing of the glass fibres, as in a mat, and particularly where made up as by spinning into yarn which is inter-engaged and crisscrossed or looped back and forth in a regularity of pattern as is the case in weaving or knitting, gives the elements I8, I have found, a capacity to coact with the surfaces between which they are compressed so as in effect to resilently grip the body of the wheel I0; apparently the many bends given the glass nbres in making up the glass mat, or the many bends given the nbres and yarn in making up the fabric cause each one of them to function as aspring. The many ilbres of the yarn when made up into the fabric or mat funcamasar' forni, underlying springyfglass filaments lend springy support to those overlying them.

When the nut I6 is tightened up, thus to drawthe assemblage against the shoulder I1, those portions of the elements I8 that underlie the' clamping faces Il* and I", which are of subness and even though they do not make complete recovery and restore the elements Il to: their initial or normal uncompressed thickness, the

stantial area,'undergo some compression as is,l

indicated with some exaggeration in the drawing by contrast with the uncompressed portions thereof that extend into the under-cuts Ilb and i I5b of the clamping members I4 and I5. Due to.

the springy action. such as above mentioned, the

elements I8 accommodate themselves to irregularities in the side faces of the wheel IB and substantially' distribute uniformly the clamping pressure exerted by the clamping members Ait and I5, to the interposed or underlying body of the wheel I0; the springiness aids in avoiding over-concentration of clamping pressure at unintentionally and possibly present high regions in the side faces of the wheel and thus aids in guarding against breakage of the wheel. The mass or glass fibres or strands, or the mass of .glass fibre yarn, I have found, tends to restore itself to initial thickness, that is, the thickness before compression, and this action may be aided by the coating material; thus Athere is a reliable follow-up action, throughout long continued operation of the wheel, in exertingk the initially applied clamping pressure against the .two sides of the Wheel center, resulting in reliable long continued gripping of the wheel and reliable opposition to such relief of the clamping pressure as would permit radial shift of the wheel due to play or looseness between the shaft It land the wheel, as above mentioned.

recovery is so substantial as to permit repeated use of the elements I8 as for repeated subsequent assemblies of the wheel unit to an operating or mounting shaft, and each time retain inherent springiness, yieldability and resiliency to function and coact generally in the manner above described.

Preferably, and if desired, the elements Id are attached in any suitable way to the respective side faces of the grinding wheel I0, and in auch l case any suitable adhesive may be-employed. The

adhesive is preferably water-resistant and resistant to oil. A suitable adhesive'to employ is latex or other rubber or resinous compositions.

The elements It, iurthermore,l can take/a suitable printing ink and hence identifying indicia,

- such as wheel size, grit size of abrasive, concentration of abrasive, etc., ete., may be printed upon This action continues unimpaired by water, oil

or other liquid coolants applied during the grinding operation for the glass of the elements i8 is unaffected thereby, and moreover, though the elements I8 might become subjected to substantial temperature rises or heating, assuming substantially the same. temperature as the body of the wheel does, such heating effects do notimpair the structure or composition or characteri istics of the glass as would be the case ify reliance were placed upon materials like leather, paper, cloth -or the like; On the contrary, as

the outer faces of the elements IIB, and the lasting qualitiesand resistance to deterioration of the elements I8, as noted above, also make for permanency of the applied identification.

4llt will thus be seen that there has been provided in this invention a wheel unit and mount-f lng arrangement' in which the various objects heretofore noted together with many thoroughly vpractical advantages are successfully achieved.

Tl'iough in the illustrative embodiment it has in the above been assumed that the wheel is of the vitriiied or ceramic bond type, the invention is to be interpreted as embodying, or as applicable to, any other type ofgrinding wheel structure or any other abrasive article, such as an abrasive stick, wheel segments, or the like, for which it is desired to achieve the many advantages of the invention, and in the claims, the term "grinding wheel, unless otherwise qua-lined, istherefore to'be interpreted to include any such abrasive compared to such materials as these, the glass of the elements I8, having a superior coeilicient of heat conduction, permit the conduction of heat from V.the body the wheel to the metal clamping members I4-I5 which are of high heat conductivity, and thus heat flow from the body of the wheel is expedited for the metal clamping members` I4--I5 can act as heat radiators or dissi-v pators, particularly when aided-by a liquid coolant that ows over them. In contrast to such actions as these, materials like leather, cloth, feit, paper, and the like are in general relatively article.

As many possible embodiments may be made of the mechanical features of the above invention and as many changes might be made in the embodiment above set forth, all without departing from the scope of the invention, it is tobe understood that all matter hereinabove set forth, or shown in the accompanying drawing, isto be interpreted as illustrative and not in a limiting sense.

I claim:

1. A grinding wheel mounting comprising. a rotatable grinding wheel support havingclamping members, and a grinding wheel having against very poor conductors of heat and thus contribute toward building up very substantialtemperatures in the body of the Wheel and in the portions directly engaged by them with theA result that deterioration of these materials by heat is a multiplylng or cumulative action.

The above-described resiliency orfollow-up ac- V tion of the glass elements I 8-I8is of aid also in maintaining sufficient tightness of gripping during dimensional changes that accompany temperature changes. Upon release of the clamping pressure, as when the wheel is removed from the shaft, the springiness of the glass fibres or strands gives the mat-like elements I8-I8 a. substantial extent'of recovery in the sense the I given the glass fibres because of the woven char.

comprising a grinding wheel having on its two side faces and throughout the areas thereof to be.

engaged by said` clamping members', mat elements of woven glass fibre, the configurations acter of the mat elements causing the'glass iibre strand elements of the mat elements to have springiness, whereby clamping pressures exerted theretofore compressed portions expand in thick E by said clamping members are yielding!! transmitted and distributed to the body ot the wheel.

3. A grinding wheel having on a. clamping face thereof a mat element of woven glass nbre, the configurations given the glass fibres because of 5 v the woven character thereof giving the glass fibre elements springiness to substantially yieldingly transmit and distribute clamping pressures to the body of the wheel.

4. A grinding wheel having on a clamping face l0 thereof an element for receiving and transmitting to the wheel the Pressure exerted by a clamping member, said element comprising glass nbres made up into yarn and the yarn made up into a mat whereby the mat is substantially seifaccommodating to irregularities in the face o! the wheel and the yieldability of the yarns effect substantially uniform distribution of the clamping pressure to the area. of the wheel engaged by the mat.

ROBERT H. LOMBARD. 

